The present application claims priority under 35 U.S.C. xc2xa7119 of German Patent Application No. 198 52 257.6, filed on Nov. 12, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety.
1. Field of the Invention
The present invention relates to a winding machine and process for winding a material web onto a winding core, e.g., a reel spool, so that a wound roll is formed on the winding core. The winding machine includes a press roll (carrier drum) that rests in two moveable bearings so as to be pressed against the wound roll via a pressing device, thereby forming a winding nip. The material web can be guided to partially surround the press roll and to run through the winding nip, which can be set with a desired line load by the pressing device. The winding core, as well as the wound roll, can be arranged within moveable bearings that displace the winding core as the diameter of the wound roll increases so as either to maintain the winding nip at least approximately the same position or to displace the winding nip by only a relatively small amount, e.g., about 10 to 200 mm, during winding. Each of the bearings of the winding core can be displaced by an associated driving device, and a control device is adapted to control the driving device as a function of displacement of the pressing roll from a desired or preferred position.
2. Discussion of Background Information
Such a winding machine is known, e.g., from German Publication No. DE 2 214 350 and its U.S. family member U.S. Pat. No. 3,834,642. Winding machines of the type generally disclosed in these documents are, for example, located at the end of a machine for producing, refining, or otherwise processing a paper web. In the known winding machine, the press roll rests in bearings that are attached to a pivoted lever. The bearings of the winding core can be moved horizontally by a threaded spindle which is provided with a drive that is controlled as a function of displacement of the pivoted levers carrying the press roll. Such a control process is initiated by the opening or closing of a contact.
As with the instant invention, the winding core and wound roll are displaced in accordance with the increase in diameter of the wound roll so that the position of the winding nip remains at least approximately the same during the winding process. However, the known arrangements do not meet the demands placed upon winding machines that serve as a part of a modem high-performance machine for producing or processing a material web. Such high-performance machines normally have a working width of up to approximately 10 m, where work speeds are achieved of around 1500 to 2500 m/min.
The demands placed on such winding machines include, e.g., that:
A. control of winding core displacement (in accordance with the increase in diameter of the wound roll) must occur in as jerk-free a manner as possible and with extreme precision.
B. movements of a press roll bed (when setting the desired line load in the winding nip) must be as small as possible and occur as slowly as possible.
C. the above requirements A and B must contribute to lessening the danger of vibrations and to minimizing the danger of the web ripping because a rip can cause enormous amounts of waste paper to result within seconds.
The present invention provides a winding machine similar in general to that discussed above that includes a position measurement device coupled to at least one of the two bearings of the press roll to produce an instantaneous position value that is dependent upon an instantaneous (current) position of the pressing roll, a regulator that compares the instantaneous position value with a desired position value and that provides an actuating variable that corresponds to the deviation of the instantaneous value from the desired value, and a wire transmitting the actuating variable from the regulator to the control device of the driving devices so that the above-mentioned requirements are fulfilled to the greatest extent possible.
Therefore, according to the invention, the position regulator is provided for the press roll to ensure that the moveable press roll can supply the material web to the wound roll while maintaining a line load which can be set as desired in the winding nip and to ensure that, in spite of the rapid increase in diameter of the wound roll, the press roll departs from a desired center position only briefly and by very short distances. During a winding process, the displacement movements of the press roll are relatively slow and never jerky, thus, the danger of vibrations and paper rips is eliminated. Moreover, it is possible to intentionally displace the position of the press roll by a relatively short distance, e.g., between approximately 10 and 200 mm, with the aid of the regulator. However, when doing so, the regulator again provides a calm and slow displacement of the press roll.
According to the invention, it has been found that an additional problem that arises in winding especially wide material webs, i.e., the material web can temporarily have very small differences in thickness across its width. Thus, the web can, e.g., be thicker by a very small amount in the region of one edge than at the other edge. This leads to the danger that a wound roll will result that is not exactly cylindrical, but rather is slightly conical. This problem may appear even more markedly in the case in which the wound rolls are produced with a particularly large diameter, e.g., between approximately 3 to 4 m. It has been recognized that such difficult conditions can be better overcome by providing the regulator with a mean instantaneous position value that is derived from measured position values collected at both bearings of the press roll.
The apparatus of present invention permits axial traversal of the material web to be created in the wound roll being produced, which solves a further problem that is discussed below.
Irregularities can occur in the thickness profile of the material web. These irregularities usually only occur briefly, especially in paper machines, because irregularities can be eliminated, e.g., by adjusting the headbox. However, small differences in thickness can adversely influence the winding structure. Thus, for example, it can happen that the winding diameter can be larger than the desired diameter at some point in the web width. This often leads to undesired local overstretching of the material web, which can have a significant effect on the flatness of printing papers, for example. Thus, the present invention provides a winding machine which, despite possible irregularities in the material web, guarantees a consistently trouble-free winding structure in as constant and reliable a manner as possible. For this purpose, the press roll (carrier drum) can be cyclically tilted relative to the travel direction of the supplied web, thereby creating an axial traversal of the material web. Thus, the press roll can be displaced or pivoted alternatingly in one direction and then in the other, so that the carrier drum and the wound roll being created on the reel spool are kept in contact with one another during the winding process, i.e., the winding nip is maintained. As a result of the cyclic tilting according to the invention, any irregularities that occur, such as an irregularly changing thickness cross-direction profile, can be distributed across a large region of the web width, so that flaws in the desired winding structure are practically eliminated and an at least approximately cylindrical winding diameter can be achieved despite any irregularities. Further, local overstretching of the material web can be prevented.
Accordingly, the present invention is directed to an apparatus for winding a material web into a wound roll on a winding core. The apparatus includes a press roll, movable press roll bearings coupled to the press roll, and a pressing device positioned to press the press roll against the wound roll. In this manner, the press roll and the wound roll form a winding nip, and the material web is guided around the press roll and through the winding nip. The pressing device is adapted to set a line load in the winding nip, and movable winding core bearings are couplable to the winding core of the wound roll and are adapted to move the winding core to compensate for an increasing wound roll diameter. The winding nip either remains in an at least approximately same position or is displaced by a small amount during winding. A driving device is positioned to move each of the movable winding core bearings, and a control device is arranged to control the driving device as a function of movement of the press roll from a desired position. A position measurement device, coupled to at least one of the movable press roll bearings, is adapted to produce an instantaneous position value of the press roll in accordance with a current position of the press roll, a regulator is adapted to compare the instantaneous position value with a desired position value of the press roll and to transmit an actuating variable that corresponds to a deviation of the instantaneous value from the desired value, and a wire is adapted to transmit the actuating variable from the regulator to the control device.
According to another feature of the present invention, the position measuring device can be coupled to each of the movable press roll bearings. The position measuring devices may be further coupled to an average value provider that transmits an average instantaneous position value derived from the two instantaneous position values to the regulator. Further, a desired value transmitter can be coupled to the regulator to provide the desired value. The desired value, while adjustable, may remain constant during a winding process. Alternatively, a desired value transmitter can be coupled to the regulator to provide the desired value, and the desired value may be variable during a winding process.
In accordance with another feature of the invention, each of the press roll bearings may be coupled to a position measuring device and to a position regulator. The driving device can include two driving devices and the control device can include two control devices, and the two driving devices may be respectively coupled to the two control devices, and the two control devices may each be coupled to receive the actuating variable output transmitted from the regulator. The regulator may include two regulators, and the apparatus can further include a desired value transmitter coupled to the desired value transmitter. The desired value transmitter may be adapted to transmit the same desired values to the two regulators. Alternatively, the desired value transmitter can be adapted to transmit a constant desired value to one of the two regulators and to transmit a cyclically variable desired value to the other of the two regulators. Further still, the desired value transmitter can be adapted to transmit to the two regulators desired values that cyclically vary opposite one another.
According to a further feature of the instant invention, the press roll can include a carrier drum, the winding core can include a reel spool, and the material web may be composed of one of paper and cardboard.
According to a still further feature of the invention, the small amount which the winding nip is displaced can be between approximately 10 and 200 mm.
The present invention also relates to a process for winding a material web that includes positioning a wound roll adjacent a carrier drum, and pressing the carrier drum against the wound roll with a pressing device, such that a winding nip is formed. The process also includes guiding the material web around the carrier drum and through the winding nip, moving the wound roll, in accordance with an increasing wound roll diameter, such that the winding nip one of remains in an at least approximately same position and is displaced by only a small amount. Further, the process includes measuring an instantaneous position of the carrier drum, comparing the measured instantaneous position of the carrier drum to a desired position of the press roll, transmitting an actuating signal which corresponds to a difference between the compared positions, and moving the wound roll in accordance with the actuating signal.
According to another feature of the instant invention, the measuring of the instantaneous position can include measuring an instantaneous position for each end of the carrier drum, and averaging the measured instantaneous positions-as the instantaneous position. Further, the desired position, while adjustable, may remain constant during winding. Alternatively, the desired position may be variable during winding.
In accordance with still another feature of the present invention, the measuring of the instantaneous position can include measuring an instantaneous position for each end of the carrier drum, the comparing can include independently comparing, in separate regulators, the respective instantaneous positions for the carrier drum ends to the desired position of the carrier drum, and the transmitting of the actuating signal may include independently transmitting actuating signals to separate devices for displacing the carrier drum. Moreover, the process can further include coupling a desired position transmitter to each of the separate regulators, and transmitting the desired position of the carrier drum to each of the separate regulators. The desired position transmitter can transmits a same signal to the separate regulators. Alternatively, the desired position transmitter may transmit a constant position signal to one of the separate regulators and may transmit a cyclically variable desired position signal to another of the separate regulators. Further, the desired position transmitter can transmit desired position signals to the separate regulators that cyclically vary with respect to each other.
According to a further feature of the invention, the process may farther include axially adjusting the position of the material web on the wound roll.
According to yet another feature of the instant invention, the process can further include pivoting the winding nip, such that the material web axially traverses the wound roll.
The present invention is also directed to an apparatus for winding a material web into a wound roll on a winding core. The apparatus can include a press roll, a pressing device being positioned to press the press roll against the wound roll, such that the press roll and the wound roll form a winding nip, and a moving device for moving the winding core of the wound roll to compensate for increasing wound roll diameter during winding. In this manner, the winding nip one of remains in an at least approximately same position or is displaced by a small amount during winding. A driving device can be positioned to move the moving device, and a control device can be arranged to control the driving device as a function of movement of the press roll from a desired position. A position measurement device is adapted to produce an instantaneous position value of the press roll in accordance with a current position of the press roll, a regulator is adapted to compare the instantaneous position value with a desired position value of the press roll and to transmit an actuating variable that corresponds to a deviation of the instantaneous value from the desired value, and the control device is coupled to receive the actuating variable from the regulator.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.